A systematic investigation to evaluate the effect of ionizing radiation upon liver microcirculation is proposed. By using objective methodology radiation induced changes in oxygen transport to tissue, blood cell aggregation, liver function liver scans, histology and ultrastructure will be determined to ascertain acute as well as late effects. Reported results of a pilot experiment show the feasibility of this approach. After proper quantitation of the inflicted insult, prevention or reversal will be attempted by systematic testing of peripheral circulation flow improvers, such as low molecular weight Dextran, and drugs known to prevent intravascular red cell and platelet aggregation or adhesiveness such as anti-adhesive drugs and aspirin. Successful completion of these experiments will immediately provide a method to allow radiation treatment of liver cancer, metastatic or primary, a disease today lacking a cure except for chemotherapy palliation.